1. Field of the Invention
The present invention concerns a seal ring comprising a deformable hollow metal element intended to be clamped between two surfaces to be applied against each other in a fluid-tight manner and a spiral spring inside the hollow deformable metal element and flexibly withstanding the deformations of the latter.
2. Description of the Prior Art
It would be thought that a seal of that type would retain its fluid-tight qualities during a very long period, due to the fact that the hollow deformable metal element would be applied with a sufficient pressure by the spiral spring on the surfaces to be applied against each other in a fluid-tight manner and to compensate the micro-defects in flatness of surfaces to maintien fluid-titht sealing. Now, it has been discovered that such seals lose their fluid-tight qualities progressively, due a creeping of the metal of the hollow deformable element between the turns of the springs, causing an application of that element on the irregularities of the surfaces to be brought together which is not so good (a phenomenon observed more particularly when there are thermal shocks).
The aim of the present invention is to overcome the above disadvantage and to produce a seal ring for surfaces to be applied against each other, such as flanges, which maintain excellent sealing after numerous successive dismantling and assembling operations, putting under pressure or under vacuum, temperature rises or lowerings.